I haven't clicked on the links, but dwarf cichlids are probably the way to go, I had a male convict in a 20 gal, but since they are territorial and a good size fish, the only thing you could put in there with him was a female which I didnt want to do since they breed like crazy. I would have rather seen him in a larger tank. basically, I wouldn't but anything that gets bigger than 4 inches.